The present invention relates to a device for preventing contact and arc prevention in a switch, more particularly to a centrifugal switch for use in starting of an induction motor.
In the prior art, a centrifugal force device of a centrifugal switch is used as it is, and it is connected in parallel with a triac only at a contact spot, further a triac takes full charge of a current burden of a contact and the centrifugal switch bears only a delicate current so as to give a trigger to the triac further. In order to solve the problem regarding centrifugal switch which is caused by a damage or a friction loss of a contact a current conducted to the triac (T1), further a current and a condenser which is connected to a winded auxiliary wire in series are connected the triac (T2), afterward the triacs (T1) and (T2) are arranged in parallel and connected to a condenser and a resistance in series, further it is connected with a switch and a resistance between the triac (T2) and a gate.
Thus, in the prior art, the triac bears a load current fully, therefore it must use a triac with a large volume under a load of a large current, as the result of the above mentioned a cooling plate also becomes larger as well as a triac volume, therefore it is not economical, and it causes a problem upon a installing place as the size of a device is large, in view of the matters a method which increases a contact volume without use of a triac is considered to be more useful.
The present invention will be described in detail referring to the attached drawings hereinafter.